P0634
DTC P0634
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
DTC Descriptor
DTC P0634
- Transmission Control Module (TCM) Overtemperature
Circuit/System Description
The transmission control module (TCM) temperature sensor is located inside of the control solenoid valve assembly which has no serviceable components. The TCM monitors the TCM sensor for over temperature protection.
Conditions for Running the DTC
* The ignition voltage is greater than 8.6 volts.
* The TCM temperature is between 0-170°C (32-338°F) for 0.25 second or greater.
* DTC P0634 has not set this ignition cycle.
Conditions for Setting the DTC
Condition 1
The TCM detects an internal temperature condition greater than 146°C (295°F) for 5 seconds or greater.
Condition 2
The ignition voltage is greater than 18 volts and the TCM detects an internal temperature condition greater than 50°C (122°F) for 2 seconds.
Action Taken When the DTC Sets
* DTC P0634 is a Type A DTC.
* The TCM defaults the transmission to reverse and 3rd or 5th gear operation.
* The TCM inhibits Tap Up/Down function.
* The TCM inhibits manual shifting of forward gears.
* The TCM commands maximum line pressure.
* The TCM shuts down.
Conditions for Clearing the DTC
DTC P0634 is a Type A DTC.
Reference Information
Description and Operation
Electronic Component Description (Electronic Component Description) for control solenoid valve assembly
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
1. Ignition ON, review the Failure Records when the DTC set. Verify the scan tool ECT Sensor parameter is less than 125°C (257°F).
• If greater than the specified range, refer to Engine Overheating (Engine Overheating).
2. Engine running, accessories OFF, measure and record the battery voltage at the battery terminals with a DMM. The voltage should be between 12.6-15.0 volts.
• If not within the specified range, or the charge indicator light is ON, refer to Charging System Test (Charging System Test).
3. Perform the Transmission Fluid Level and Condition Check (Transmission Fluid Level and Condition Check) to verify correct fluid level and condition.
4. Perform the Transmission Fluid Cooler Flushing and Flow Test (Transmission Fluid Cooler Flushing and Flow Test) to verify proper transmission oil cooler flow.
5. Operate the vehicle within the conditions for running and setting the DTC until normal engine temperature is reached. Verify the scan tool TCM Temperature parameter is less than 146°C (295°F).
• If greater than the specified range, inspect the transmission cooling system for obstructions to the airflow of the radiator or transmission due to debris, kinked, or damaged transmission fluid lines, or damage to the transmission cooler. If all the items test normal, replace the control solenoid valve assembly.
6. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Repair Instructions
Important:
* Perform the Service Fast Learn Adapts (Programming and Relearning) following all transmission related repairs.
* Before replacing the TCM, perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection (Control Solenoid Valve and Transmission Control Module Assembly Inspection).
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
Control Module References (Programming and Relearning) for control solenoid valve assembly replacement, setup, and programming